In recent developments in intelligent transport systems (ITS), detection of a location where anomalous traveling in the road width direction occurs (anomalous travel location) due to, for example, avoidance of an obstruction has been increasingly desired. Detecting such anomalous travel locations will offer users, for example, notification of anomalous travel locations or drive assistance in consideration of anomalous travel locations.
Conventional devices for detecting anomalous travel locations include a deviation identification device that identifies any deviation of the vehicle from the lane (see Patent Document 1, for example). The deviation identification device uses road image data taken by an on-board imaging device or the turning degree of the vehicle to determine whether the vehicle is likely to deviate from the lane.